HTTP Multipart Request Example

HTTP Multipart Request Example

This example application illustrates how to use Mule ESB to build a simple HTTP application with the file-submit form. After reading this document, and creating and running the example, you should be able to use what you have learned to create an HTTP request-response application that processes incoming HTTP requests containing submitted file data and stores the data in a file system.

Assumptions

This document describes the details of the example within the context of Anypoint™ Studio, Mule’s graphical user interface (GUI). This document assumes that you are familiar with Mule ESB and the Anypoint Studio interface.

Example Use Case

In this example, a user submits a file in the HTML form that is sent via HTTP to Mule Runtime. The application receives the data, extracts some properties, and stores the data in the specified directory of the file system.

Set Up and Run the Example

As with other examples, you can create template applications straight out of the box in Anypoint Studio. You can tweak the configurations of these use case-based examples to create your own customized applications in Mule.

Follow this procedure to create and run the application:

1. Open the HTTP Multipart Request example project in Anypoint Studio from Anypoint Exchange.
2. In your application in Studio, click the Global Elements tab. Double-click the HTTP Listener global element to open its Global Element Properties panel. Change the contents of the port field to required HTTP port (e.g., 8081).
3. Set the working directory in File Connector configuration element.
4. In the Package Explorer pane in Studio, right-click the project name, then select Run As > Mule Application. Studio runs the application and Mule is up and kicking!
5. Open your browser and hit http://localhost:8081/uploadFile.
6. Click Browse and choose a file to upload. Then, click Send.

Either you will see the file contents in your browser or a dialog will prompt you to save the file contents, depending on the type of file.

How it Works

The HTTP Multipart Request example application consists of two simple flows that receive end user HTTP requests, set payloads based on the request paths and sent data, and return the payloads to end users as HTTP responses.

The sections below elaborate further on the configurations of the application and how it works to respond to end user requests.

httpRenderFlow

This flow makes use of two building blocks to receive and respond to an end user requests. When an end user request reaches the application, the first building block it meets is HTTP Listener. Because the flow has a two-way message exchange pattern, this HTTP endpoint is responsible for both receiving requests from and sending responses to the end user.

Then, the Parse Template component loads an HTML document from the specified location and Mule moves the message back to the end user in the form of HTML.

httpMultipartRequestFlow

This flow receives only POST requests as specified in the HTTP component.

The Set Variable component extracts the name of the attachment and stores the name in the variable fileName.

The Logger component prints the content-type of the incoming file attachment to the console.

The Set Payload component sets the file contents as the payload.

Finally, the flow returns the message payload as the response to the end user.